Field of Invention
This invention relates to a method which utilizes plasma scattering for removing residual materials which remain in a cavity of a multi-layered semiconductor device on which respective patterns have been formed after an etching process has been performed.
In the process for manufacturing multi-layered semiconductor memory devices having a capacity of more than 1 mega bit, cavities are formed in the semiconductor device. Accordingly, residual materials which should be removed upon etching remains in the cavity. Such residual anisotropic etchable material is an impurity which affects the property of memory device and should be removed to improve the quality of the device.
In the prior art, methods for removing the residual anisotropic etchable material in the cavities of a semiconductor device are as follows:
The first, extending the etching time to remove the residual materials. However, this attempt presents a problem in that if the selectivity of the etching solution is low, other films, which must not be etched, are etched. Thus, the selectivity if the etching solution toward the materials must be extremely high and be extremely low toward the other films in order not to etch the necessary portions of the other films.
The second, performing an additional mask pattern process and an additional etching process on only the residual material contained in the cavity in order to remove the residual material. That is, the residual, material to be removed from the cavity and the top the adjacent film (of the other material) are coated with a photoresistive film. Then a portion of the photoresistive film positioned on the residual material contained in the cavity is removed. Then, an additional etching process is performed to remove the residual material from the cavity.
Therefore, the process for removing the residual material is complicated because such process requires the additional formation of photoresistive film and an additional etching step. Also, the mask pattern forming process should be performed very carefully so that a resulting delay in the process for manufacturing the semiconductor device occurs.
Therefore, it is an object of the present invention to solve the problems presented in above mentioned prior art methods.
it is a further object of the present invention to provide a method for removing residual material in a cavity of the semiconductor device by utilizing plasma scattering.